Etching of buried photoresist layers and its application to the formation of three-dimensional layered structures

The fabrication of three-dimensional layered structures with 180-nm-thick TaO_x top layers supported by 1.5-μm-thick Mo pillars formed on a glass substrate is presented. The photoresist used for planarization was successfully removed through the TaO_x layers using heat treatment at 270 °C with mixed vapors of ethyl alcohol and pure water at high pressure for 3 h. Vacancies underlying the TaO_x layers were consequently formed. The possibility of rapid and lateral crystallization of amorphous silicon films was demonstrated when the silicon films formed on the TaO_x overlaying the vacancy regions were irradiated using a frequency-doubled YAG laser at 250 mJ/cm². Energy sensors using Cr/Al metal wires, with a high sensitivity of 0.07 mW/cm², were also demonstrated using the present structure with vacancy regions for reduction of heat diffusion. Received: 22 January 2001 / Accepted: 24 January 2001 / Published online: 27 June 2001     

Stabilisation of fcc cobalt layers by 0.4 nm thick manganese layers in Co/Mn superlattices

Epitaxial Co/Mn multilayers (0.75 to 6 nm Co, 0.4 nm Mn layer thickness) have been grown on mica substrates covered by a (0002) Ru buffer layer. The structural properties of these layers have been studied using X-ray diffraction, nuclear magnetic resonance (NMR), and high resolution transmission electron microscopy (HRTEM). The Co layers, grown as face centred cubic (fcc), were found to be stabilised by the very thin Mn layers. Data obtained using X-ray diffraction and NMR were analysed and found to be in good agreement, while Monte-Carlo simulations were used to interpret the data and calculate the expected diffracted intensity and NMR spectra. The HRTEM data show that the Mn layers give rise to a large strain contrast extending, in the growth direction, over a distance which exceeds the thickness of the Mn layers. The superlattices could be described as having an fcc structure containing randomly located stacking faults with varying densities. The results verify the presence of a dominant, almost perfect phase of fcc stacking, and of a faulted hcp phase, while the number of defects increases with the Co layer thickness. Received 27 October 1999 and Received in final form 29 May 2000     

复合X光激光中复合阶段拉氏点的特性

给出了拉氏点在进入Ne/Te增益目标区域后,其电子密度、电子温度、裸核布居概率、类H离子2–1线逃逸概率和增益随时间变化的近似估计式,以及拉氏点进入Ne/Te增益目标区域的时间tg与电子温度Teg必须满足的关系。     

10MeV LIA强流电子束的聚焦

研究了10MeV直线感应加速器（LIA）的输出束在螺线管透镜作用下的聚焦特性。通过解非线性电子轨迹方程获得实验所需的磁场范围,并解析分析空间电荷效应、发射度、透镜球面像差和色散像差对最小焦斑直径的限制,同时,对束质心螺旋运动影响束聚焦的情况亦做了较为详细的分析。实验结果表明：在合适的螺线管聚焦磁场下,可获得直径≤6mm的电子束焦斑,与理论分析结果基本一致。     

波导FEL振荡器的孔耦合输出特性

波长500μm的远红外自由电子激光振荡器,是由平面波导和两个对称金属柱面镜组成的半封闭光腔。由于反射镜具有反射率,在下游镜的轴上开一个半径为Rh的圆孔来输出功率。孔耦合输出是一种简单、有效的输出方式,并可以广谱输出。缺点是抽取率随波长变化,计算很复杂。本文给出了用三维程序数值模拟结果。给出了腔内功率,输出功率,抽取率及腔镜边缘的衍射损失随小孔半径的变化。结果表明,选取适当的孔径,既可以有效地输出功率,又能保持较高的腔内功率和较纯净的腔模。     

光电过程原子能级截面大量计算的实现

在HFR方法的基础上,考虑束缚组态间的相互作用,解决了Cowan程序光电计算过程中小能量区间误差偏大及一次计算自由电子能量范围受限制的问题,确定了阈能点的计算方式,从而使大量计算成为可能。分析证明了计算结果的正确性并估计了计算精度。并对锂、钠与铯原子计算的结果与参考文献做了比较,从理论上分析了能极水平光电截面求和后的结果与轨道水平光电截面的过渡关系与差别。     

Hamiltonian of a Slightly Asymmetric Molecules with a Three Fold Internal Rotor and Its Applications to Optically Pumped FIR Lasers: Theoretical Aspects

In this paper, a Model of the Hamiltonian function is reviewed for the slightly asymmetric class of molecules, which is the most successful so far, according to our present knowledge. This model does not have the redundancy problem suffered by previous models. The observed frequencies are calculated to within experimental accuracy. In our subsequent papers we will show the application of this model for the prediction and quantum number assignments of optically pumped far infrared lasers and thereby increasing the possibility of new lines in the region of the spectrum which severely lacks enough monochromatic sources. We will also show that this model is capable of calculating even MMW transitions for the second excited state of methanol. All the previous models consider transitions up to the first excited torsional state.     

Energy transfer and excited state lifetime of some anthracene laser dyes

The lifetimes of some anthrathene derivatives in different solvents have been determined using the phase modulation method. The lifetime of 10-phenyl-2-methyl-9-acetoxyanthracene and 10-(4-acetoxyphenyl)-2-methyl-9-acetoxyanthracene were found to equal 11 and 11 ns in methanol, respectively. Energy transfer from 10-phenyl-2-methyl-9-acetoxyanthracene and 10-(4-acetoxyphenyl)-2-methyl-9-acetoxyanthracene to rhodamine B and rhodamine 110 in different solvents has been studied by using steady-state emission measurements. The large values of the critical transfer distance R₀ and the rate constant of energy transfer k_ET suggest that the mechanism is long-range dipole–dipole energy transfer as described by Förster.     

Coulomb interactions of massless Dirac fermions in graphene; pair-distribution functions and exchange-driven spin-polarized phases

The quasi-2D electrons in graphene behave as massless fermions obeying a Dirac-Weyl equation in the low-energy regime near the two Fermi points. The stability of spin-polarized phases (SPP) in graphene is considered. The exchange energy is evaluated from the analytic pair-distribution functions, and the correlation energies are estimated via a closely similar four-component 2D electron fluid which has been investigated previously. SPPs appear for sufficiently high doping, when the exchange energy alone is considered. However, the inclusion of correlations is found to suppress the spin-phase transition in ideal graphene.